Some of the sharpest responses to the current uncomfortable relations between Islam and the nominally Christian west have come from writers of fiction for children and young adults. Contemporary stories by the likes of Leicester-based Bali Rai set the conflict at street level, telling tales of ethnic tension in the classroom or on the football pitch. Other authors, such as Elizabeth Laird, look to the past for a way of tracing that same faultline. Here she uses the third crusade of the late 12th century - that magnificent jumble of good intentions and twisted thinking - as the background for an engaging if somewhat predictable account of how two children from different faiths come to a revised understanding of one another's culture.

Adam is a serf from the English midlands who is convinced that the only way his dead mother will get to heaven is if he is able to scatter some soil from Jerusalem over her village grave. In order to obtain this stony beneficence he joins up for service under the local feudal knight. Salim, meanwhile, is a Muslim boy of the same age who has been apprenticed to Saladin's personal physician. Slowly the boys' paths move towards each other, coming together outside the port of Acre where the Christian and Saracen armies engage in a bad-tempered stand-off that lasts for months.

Laird uses a series of encounters between the two boys as a chance to confound mutual misapprehensions. Adam knows for a fact that the infidels are Christ-denying savages who indulge in polygamy and strange, obscure cruelties. Salim, meanwhile, believes that the "Franks" (his phrase for the job-lot of Europeans who have barged into his homeland) are dirty drunkards whose beliefs are a jumble of near-pagan superstitions.

Over 400 pages the boys are made to rethink their positions. Adam learns that the Saracens are peaceable (even the great Saladin talks about spreading "rose-water rather than blood"), good at maths and way ahead of the Christians when it comes to personal hygiene. Far from being denied, Christ is revered as the greatest prophet after Muhammad. There might even be something to be said for polygamy.

There is, in truth, less for Salim to discover about the Franks, who remain primitive thugs incapable of having a good wash. The medical apprentice is appalled to watch as a wounded crusader has his skull cracked open by Christian doctors in order to release an imaginary demon. In fact, the only positive thing that Laird allows her young Muslim hero to discover about the enemy is that they are as brave as lions.

Throughout her narrative she is careful to sprinkle things that have a contemporary resonance which she then proceeds to confound. Thus Basra and Baghdad are mentioned as places of abiding peace and culture to which the war-weary of the Middle East flock for respite. The Kurds are autonomous warriors who excel in horsemanship. Polo is the favourite sport not of red-faced English barons, but of nimble Saracens. None of this is subtle but it is well-intended, and while Crusade lacks the imaginative power of the most enchanting children's historical writing, it is a sturdy attempt to show young teenagers that their Muslim contemporaries come from a culture that is as civilised and peaceable as their own - or perhaps more civilised.

· Kathryn Hughes' biography of Mrs Beeton is published by Harper Perennial. To order Crusade for £9.99 with free UK p&p call Guardian book service on 0870 836 0875 or go to guardian.co.uk/bookshop